The present invention relates to a measurement method and system, and more particularly, to a method and system for measuring the mean diameter and mass concentration of suspended particles in a fluid.
In the method of measuring fluid flow using the Doppler principle, the particles suspended in the fluid reflect or scatter the ultrasonic signal transmitted by the one or more transducers. The energy of the Doppler return signal reflected or scattered is related to the diameter and mass concentration of the particles. When the diameter of the particles is small or the mass concentration is low, the return signal is weaker; when the diameter of the particles increases or the mass concentration increases, the return signal also becomes stronger. However, on the one hand, when the diameter of the particles is too large, due to their own weight being too heavy, the suspended particles have a larger velocity relative to the fluid itself, in this case, if the movement velocity of the suspended particles is still used as the movement velocity of the fluid itself, it will reduce the accuracy of the flow measurement; on the other hand, when the mass concentration of the particles is too large, the attenuation of the ultrasonic signal in the fluid is also larger, where the return signal received by the one or more transducers is also weaker, with even a lower signal-to-noise ratio affecting the measurement of flow rate. Therefore, it is particularly important to measure the diameter and mass concentration of the particles during the process of measuring the flow rate of a fluid using the Doppler principle.